Many projects require compacting a surface. For example, various types of construction projects may require compacting surfaces formed by substances like soil, gravel, and asphalt. Various types of specialized machines exist for compacting such surfaces, including, but not limited to, surface rollers and vibrating plates. Such surface compactors operate by applying downward force on the surface with a base of the surface compactor, which base may include, for example, one or more rollers and/or one or more base plates.
Some surface compactors include a vibratory mechanism for generating a fluctuating vertical force on the base of the surface compactor to enhance surface compaction. The results achieved by such a surface compactor may depend in part on the amplitude of the fluctuating vertical force generated by the vibratory mechanism. Accordingly, there exist various control methods for adjusting the magnitude of the fluctuating vertical force to achieve different results. In many existing vibratory compactors, a single base plate is welded to the bottom of the vibratory unit. In some instances, an engine or hydraulic motor controllably rotates at least one eccentric mass to impart vibratory motion at a particular frequency to the base plate. The result is an oscillatory force with the frequency of the speed of rotation, and an amplitude dependent on the mass eccentricity and speed of rotation. Variations on this basic system include multiple eccentric weights and/or shafts such that by changing the phasing of the multiple weights and/or shafts, the degree of force created by the eccentric masses can be varied. Vibratory compactors may also include a removable base plate, such that various sized and shaped base plates may be used with the same vibratory mechanism, and worn or damaged base plates may be readily replaced. In cases where the base plate is removable, a locking mechanism is provided to hold the base plate in place during operation of the vibratory compactor. Existing locking mechanisms for removable base plates on vibratory compactors usually require separate structures and control systems that require multiple control inputs and must be operated independently from the hydraulic lines and fluid flow used for operating the vibratory mechanism.
European Patent EP 2083123 A2 to Schrode (“the EP '123 patent”) discloses a vibratory compactor with a removable base plate. In the EP '123 patent a quick-release latch is actuated by a double-acting hydraulic cylinder configured to receive hydraulic fluid from an excavator that operatively carries the vibratory compactor. Although the EP '123 patent provides a means for removably attaching a base plate to a vibratory compactor, a special hydraulic connector and associated additional hydraulic lines are required for connection to the hydraulic fluid supply of the excavator. The hydraulic connector includes two pressure ports, and each of the pressure ports is connected to an input of a valve that supplies the pressurized hydraulic fluid to a two-position, 4-way control valve. The control valve must be actuated independently from the direction of flow of hydraulic fluid from the excavator in order to control the supply of hydraulic fluid to the double-acting hydraulic cylinder for locking and unlocking the base plate. The base plate remains locked regardless of which direction the hydraulic fluid is flowing to and from the hydraulic motor used to operate a vibratory mechanism, and the vibratory mechanism may be operated in both flow directions.
Although the EP '123 patent discloses an apparatus and method for removably attaching a base plate to a vibratory compactor, the additional hydraulic connector, associated additional hydraulic lines, and additional control valves requiring user inputs to lock and unlock the base plate increase costs, operational control complexities, operator training, and servicing challenges. Additionally, the ability to operate the vibratory mechanism in either direction of hydraulic fluid flow from the excavator, while also using the hydraulic fluid flow from the excavator to lock and unlock the base plate increases the complexity and costs associated with the locking mechanism.
The methods and apparatus for locking a removable base plate of a vibratory compactor according to the present disclosure solve one or more of the problems set forth above.